Improved car-spring



UNTTED STATES PATENT OEEIcE.

RICHARD vosE, oENEw YORK, N. Y.

IMPROVED CAR-SPRING.

Specification forming part of Letters Patent No. 68,134, dated August27, 1867.

To all whom it may concern:

Be n known that I, RmHARn vosn, of the' city, county, and State of 4NewYork, have invented a new and Improved Volute Spring; and I do herebydeclare the following to be a full and exact description thereof,reference being hadto the accompanying drawings, forming a part of thisspecification, in which- Figure l is an elevation of my improved spring;Fig. 2, a central vertical section thereof, and Fig. 3 a diagramillustrating the form of the ends of the bar before it is coiled in theconstruction ofA said spring.

The nature of my invention relates to the shape of the bar forming avolute spring.

Heretofore volute springs have been constructed out of oblong plates ofmetal, as

` shown in Fig. 3,01 uniform width from end to end, except that at theends or opposite sides a very acute angular piece is cut from the plate,(see a. a, Fig. 3,) so that when the plate is coiled into a spring thetop and base will be in horizontal planes parallel to each other, givingto the spring at top and bottom an even bearing all around. But by thuscutting an angular piece from the end forming the inner coil, this endis left so much smaller in width that if the spring be brought home, orcompressed into the smallest possible compass, this inner coil (whichreceives and carries, the full weight of the load) receives no support,because of its inferior width, and is consequently liable to be' brokenby any unusual pressure or unequal strain coming upon the center of thespring.

The nature of my invention consists, first, in bending the inner end ofthe bar as illustrated at b in Fig. 4, so that its upper edge shall havethe angle heretofore obtained by cutting therefrom an angular piece, c,in Fig. 3 5 but its lower edge, instead of continuing in a right linewith the remainder of the bar, shall be bent in a line parallel to theupper edge, and the width of the bar thus kept uniform to its extremeinner end, leavingfthe inner coil equal in width to the remaining coils,so that when the spring is compressed all the coils shall receive equalsupport. The bar so formed may be made of uniform thickness, as well asof uniform width, or be transversely or longitudinally corrugated.

I have found that a more economical form of springmay be obtained byvaryingthe thickness of the bar so as to place the greatest weight ofmetal at the point of greatest strain, providing, also, for a propertempering of the spring.

My invention consists, therefore, in the second place, in making myimproved spring of metallic bars rolled thinner in the centerlongitudinally than. at the edges, in such manner as that the bar shallpresent transversely a double-concave section, as seen in Fig. 2 of thedrawings. This form may be imparted to the bar by passing the same, inits heated state, between double-converted roilers; and the springs maybe constructed by coiling the heated bars, formed and shaped asdescribed, upon a mandrel into a cylindrical form, and then forcingthecoils from the center outwardly with a uniform pitch by means of asuitable conical punch, the spring being supported over a hollow anvilor support, the counterpart of the punch, or they may be coiled andformed upon the coiling-machine patented by C. G. Gardiner, May 10,1857.

Having thus fully described my invention,

I claim therein as new and desire to secure by Letters Patent- 1. Avolute spring so constructed as that its topxand base shall be inhorizontal or parallel planes, and its inner coil be uniform in widthwith those succeeding it, substantially as herein described.

2. A volute spring constructed of a metallic bar gradually increasing inthickness outwardly from its center to its edges throughout its length,substantially in the manner herein set forth.

The foregoing specification of my improved enlarged edge volute springsigned by me this 6th day of June, A. D. 1867.

BICHD. VOSE. Witnesses:

ALBERT L. BUTLER, JAs. GILLET.

